Monthly Archives: October 2012

Just three weeks ago I wrote here (Few news from Mars …….) a post on a study that provided disappointing evidence that Martian clay would not have been made ​​with liquid water. With that, existence of water on Mars should be less likely, and therefore life in this planet.
However, this past week the NASA’s Curiosity rover sent us a picture of the Martian surface rocks with an aspect which seem to be the product of a stream in the past.

Photo sent by Curiosity, possible evidence of a streambed on Mars. The width of the image is about 1 meter. Image: NASA / JPL-Caltech / MSSS.

According to NASA scientists, the shapes of these stones and their arrangement as gravel, are evidence of the remains of an old water streambed flowing down the slopes of Gale Crater, where the spacecraft mission to Mars Science Laboratory Curiosity landed in early August. This place has been called Hottah by NASA, by reminiscence of a rock formation in Canada with that name.

Part of Gale crater where the mission of the Curiosity landed (the small cross inside of the ellipsis). Image: NASA / JPL-Caltech / UofA

Details of the photo (see below) show that these rocks are a conglomerate of stones, some of which are rounded and therefore likely product of water transport. From the size of gravels it carried, NASA scientists even have calculated that the water was moving about one meter per second, so it was a very impetuous flow.

So this would be another evidence that in the past Mars had liquid water, and therefore the chances of life there have been increased. In fact, this is not the first finding that points to the possibility that there was water on Mars, since the first mission Mariner 9 in 1971 had already seen geological formations that seemed river beds and canyons .

In addition to the clays that I mentioned in my previous post, another possible evidence of water was found a year ago, when the Opportunity rover (much more “primitive” than the Curiosity), which is in Mars for 8 years, found bright veins of a mineral (picture here below), apparently gypsum, in Endeavour crater. As gypsum is formed by sedimentation with water on Earth, it is likely that this was the origin of that material on Mars some thousand million years ago.

The NASA scientists say these photos taken now by Curiosity are a great evidence of liquid water. Anyway, I do not want to be faithless, but I do not know if these stones and their arrangement could have been made otherwise, who knows, other liquid materials, or wind erosion, I do not know.

Well, as the same scientists from NASA say, this Curiosity mission planned for two years is beyond the visual confirmation of an old streambed. Analyses that the Curiosity equipment will do should allow to understand the chemical composition of these materials and their origin, trying to learn when and why Mars was dry, if the planet had been wet before. For this reason, Curiosity has to explore Mount Sharp, which is about 6 km from the center of the crater where it landed. At the base of this mountain there are clays and sulfates, according orbital observations, and therefore Curiosity will climb this mountain, 700 meters high, and there will help scientists decipher the history of Mars, wet and dry, and find some other evidences of the possibility of past life on Mars, and its habitability today.